Comment 10 for bug 600642

In my case, java-6 plugin does show in the plugin list, so it is not a problem of symlinks or such so.
When trying to open a page with a java applet, it does not work and the java panel shows errors like this:

java.lang.ClassCastException: sun.awt.motif.MToolkit cannot be cast to sun.awt.X11.XToolkit
 at sun.awt.X11.XEmbeddedFrame.addNotify(XEmbeddedFrame.java:53)
 at sun.plugin2.main.client.PluginEmbeddedFrame.addNotify(PluginEmbeddedFrame.java:46)
 at sun.awt.X11.XEmbeddedFrame.<init>(XEmbeddedFrame.java:43)
 at sun.awt.X11.XEmbeddedFrame.<init>(XEmbeddedFrame.java:60)
 at sun.plugin2.main.client.PluginEmbeddedFrame.<init>(PluginEmbeddedFrame.java:37)
 at sun.plugin2.main.client.PluginMain$StartAppletRunner.run(PluginMain.java:929)
 at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
 at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
 at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
 at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
 at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
 at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
 at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
 at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
PluginMain: could not create embedded frame

The same page loads fine with this plugin in firefox 3.0.19.